Diagnosing Hemophilia: Methods and Key Considerations

Hemophilia is a rare genetic disorder that affects the blood's ability to clot properly, increasing the risk of excessive bleeding both externally and internally.

This condition arises due to a deficiency in specific clotting factors—proteins essential for normal blood coagulation. Diagnosing hemophilia involves a thorough review of a patient's medical and family history, along with specialized blood tests that assess clotting factor levels. Below is an overview of the diagnostic process.

Family History Assessment

Since hemophilia is a hereditary disorder, doctors often begin the diagnostic process by investigating a patient's family history. Hemophilia is primarily passed down through the X chromosome, making it more common in males. As a result, medical professionals typically examine male relatives, such as fathers, uncles, and grandfathers, for a history of the condition. However, approximately one-third of hemophilia cases occur without a known family history, meaning that the absence of affected relatives does not rule out the disorder.

Complete Blood Count (CBC)

If a familial risk is identified, doctors may order a complete blood count (CBC), a standard test used to evaluate overall blood health. A CBC measures hemoglobin levels, which are responsible for carrying oxygen through the bloodstream, as well as the number of red and white blood cells. While hemophilia does not directly affect red blood cell counts, patients with prolonged or excessive bleeding may exhibit lower hemoglobin levels due to blood loss, which can serve as an early indicator of the condition.

Blood Clotting Time Tests

When hemophilia is suspected based on initial blood tests, further screening is conducted through clotting time tests, such as the Activated Partial Thromboplastin Time (APTT) test and the Prothrombin Time (PT) test. These tests measure how long it takes for a patient's blood to clot. An extended clotting time suggests the possibility of a clotting disorder, prompting further investigation into specific clotting factor deficiencies. Since APTT and PT tests assess different clotting pathways, they are often performed together to provide a more comprehensive evaluation.

Clotting Factor Assays

If preliminary tests suggest hemophilia, doctors perform clotting factor assays to confirm the diagnosis and determine its severity. These tests measure the levels of specific clotting factors in the blood. Hemophilia severity is classified as follows:

• Mild hemophilia: Clotting factor levels between 5% and 50% of normal
• Moderate hemophilia: Clotting factor levels between 1% and 5%
• Severe hemophilia: Clotting factor levels below 1%

This classification helps guide treatment decisions, as patients with severe hemophilia are at greater risk for spontaneous bleeding episodes and require more intensive management.

Prenatal Diagnosis

Advancements in medical technology have made it possible to diagnose hemophilia before birth. After the 11th week of pregnancy, fetal DNA can be tested for genetic mutations associated with hemophilia. By the 18th week, a fetal blood sample can be analyzed to assess clotting factor levels. However, because these procedures are invasive, they are generally recommended only for pregnancies in which there is a known family history of hemophilia and the fetus is male.

Conclusion

Diagnosing hemophilia requires a combination of family history assessment, blood tests, and advanced clotting factor analysis. While early detection is crucial for effective management, genetic screening offers new opportunities for identifying hemophilia before birth. With continued advancements in diagnostic methods, individuals with hemophilia can receive timely and tailored medical care to improve their quality of life.